Gastroesophageal reflux disease (GERD) is a common upper-gastrointestinal disorder with a prevalence of approximately 5 percent in the Western world. GERD is a condition in which acidic contents of the stomach flow inappropriately from the stomach into the esophagus. GERD causes heartburn when accompanied by irritation of the esophagus. Chronic irritation of the esophagus leads to inflammation of the esophagus, known as esophagitis. In addition to esophagitis, complications of GERD include Barrett's esophagus, esophageal stricture, intractable vomiting, asthma, chronic bronchitis, and aspiration pneumonia. Approximately 25 percent of individuals with GERD fail pharmacological therapy and become candidates for a surgical anti-reflux procedure. The estimated total direct and indirect costs of GERD treatment in the United States are in excess of 100 billion dollars annually.
The focus of attention in understanding the pathophysiology of GERD has for many years been the lower esophageal sphincter (LES), thought to be a ring of smooth muscle located at the gastroesophageal junction (GEJ) near where the lower esophagus communicates with the entrance to the stomach. Normally the LES allows food to pass from the esophagus to the stomach, while otherwise remaining closed, thus preventing reflux. Closure of the LES is an active process, requiring a combination of proper mechanics and intact innervation. Additionally, the diaphragm may act on the esophagus normally to keep it closed at the LES.
Backflow of gastric contents into the esophagus results when gastric pressure is sufficient to overcome the pressure gradient that normally exists at the GEJ or when gravity acting on the contents is sufficient to cause flow through the GEJ. This situation arises when the gastric, pressure is elevated or when the competence of the LES is compromised. Gastric pressure is elevated in association with eating, bending at the waist or squatting, constriction of the waist by clothing, obesity, pregnancy, partial or complete bowel obstruction, etc. Gravitational effects occur when a patient with this condition becomes recumbent. Incompetence of the LES can be functional or anatomic in origin. Functional incompetence is associated with hiatus hernia, denervation, myopathy, scleroderma, and chemical or pharmacological influences (smoking, smooth muscle relaxants, caffeine, fatty foods, and peppermint). Dodds W J et al. 1982, N Engl J Med 307:1547-52. Anatomic incompetence is associated with congenital malformation, surgical disruption (myotomy, balloon dilatation or bouginage), neoplasm, etc.
Recently, the existence and importance of the gastroesophageal flap valve have come to be appreciated as a significant first line of defense against GERD. Hill L D et al. 1996, Gastrointest Endosc 44:541-7; Contractor Q Q et al. 1999, J Clin Gasroenterol 28:233-7. The gastroesophageal flap valve appears as a semicircular musculo-mucosal fold extending for 3-4 cm along the lesser curvature of the stomach.
The recent advent of a range of new medications for the treatment of reflux disease, including omeprazole and other proton pump inhibitors, high-dose histamnine-2 antagonists, and cisapride, has markedly improved the treatment for many patients. Despite these dramatic advances in medical therapy for GERD, they are not always fully satisfactory. There are cost implications of very long-term treatment of patients with these relatively expensive medications (Spechler S J 1992, N Engl J Med 26:786-92) as well as some concern about the safety of very long-term potent acid suppression with the possibility of gastrin (G) cell hyperplasia (Solcia E et al. 1993, Aliment Pharmacol Ther 7(supp. 1):25-8; Poynter D et al. 1985, Gut 26:1284-95; Lambert R et al. 1993, Gastroenterology 104:1554-7) from prolonged hypergastrinemia. Furthermore, a significant number of patients are resistant to or intolerant of available medical therapy (Klinkenberg-Knol E C and Meuwissen S G 1988 Aliment Pharmacol Ther 2:221-7; Klinkenberg-Knol E C and Meuwissen S G 1989, Digestion 1:47-53), and many patients relapse quickly if medical treatment is stopped. Hetzel D J et al. 1988, Gastroenterology 95:903-12.
Although several open surgical procedures are effective in the treatment of GERD, they are now used in a minority of patients because of the major nature of the surgery and the occasionally poor results achieved. These occasionally poor results may be due in part to the lack of clear patient selection criteria. At least ten different open antireflux operations have been described and used in patients. Jamieson G G, ed. 1988, Surgery of the Oesophagus London: Churchill Livingstone, 233-45. The principal types of operations have included some type of reconstruction of the antireflux barrier, which may include a gastric wrap, as in classic Nissen fundoplication (Nissen R 1956, Schweiz Med Wochenschr 86:590-2; Polk H C et al. 1971, Ann Surg 173:775-81; DeMeester T R et al. 1986. Ann Surg 204:9-20), Toupet fundoplication (Thor K 1988, The modified Toupet procedure, In: Hill L et al., The Esophagus, Medical and Surgical Management, WB Saunders Co., pp 135-8) or Belsey repair (Skinner D B et al. 1967, J Thorac Cardiovasc Surg 53:33-54), a nongastric wrap, e.g., the Angelchik prosthesis (Starling J R et al. 1982, Ann Surg 195:686-91), a ligamentum teres cardiopexy (Rampal M et al. 1967, Presse Medicale 75:617-9; Pedinielli L et al. 1964, Ann Chir 18:1461-74; Janssen I M et al. 1993, Br J Surg 80:875-8), and fixation of a part of the stomach to an immobile structure, e.g., the preaortic fascia, as in the Hill repair (Hill L D 1967, Ann Surg 166:681-92) or the anterior rectus sheath (as in an anterior gastropexy). Boerma J 1969, Surgery 65:884-9. Several of these operations also include a crural repair of the esophageal hiatus in the diaphragm. In the 1950s, Collis popularized gastroplasty as an alternative operation for gastroesophageal reflux, especially for those patients with a short esophagus. Collis J L 1957, J Thoracic Surg 34:768-78. He created a gastric tube (neoesophagus) in continuity with the shortened esophagus, which effectively increased the total and intra-abdominal length of the esophagus and resulted in clinical improvement in patients with GERD. Collis J L 1968, Am J Surg 1 1-5:465-71.
With the development of minimally invasive surgical techniques, especially laparoscopic cholecystectomy in the early 1990s, a few of the open surgical antireflux operations were developed and modified for use with laparoscopy. The laparoscopic Nissen fundoplication is currently the most widely used laparoscopic antireflux operation. Jamieson G G et al. 1994, Ann Surg 220: 137-45. Other laparoscopic antireflux operations, for example the laparoscbpic Hill repair (Kraemer S J et al. 1994, Gastrointest Endosc 40:155-9), ligamentum teres cardiopexy (Nathanson L K et al. 1991, Br J Surg 78:947-51), and some modified operations with partial wraps (Cuschieri A et al. 1993, Surg Endosc 7:505-10; McKeman J B 1994, Surg Endosc 8:851-6) have also been reported. These laparoscopic antireflux operations appear to produce good results with relatively short, pain-free postoperative recovery times in most patients. Falk G L et al. 1992, Aust N Z J Surg 62:969-72. However, laparoscopic operations themselves remain lengthy, technically demanding procedures requiring general anesthesia, best reserved for a small subset of patients with severe symptoms refractory to proton pump inhibitor or other medical treatments for GERD.
Attempts at laparoscopic transgastric antireflux surgery in animals have also been reported. Jennings et al. developed a method of forming a gastric fundoplication by creating an esophageal intussusception and plicating the gastric fundus around the esophagus using a purpose-built stapling device. Jennings R W et al. 1992, J Laparoendosc Surg 2:207-13.
There have been some attempts to treat reflux disease at flexible endoscopy. An early endoscopic approach to control GERD was to inject collagen in and around the LES. O'Connor and Lehman treated ten patients by this method with some success, although some patients required further injections at the LES to maintain symptomatic relief. O'Connor K W and Lehman G A 1988, Gastrointest Endosc 34:106-12. Donahue et al. demonstrated that GERD, induced with high-dose intravenous atropine in dogs, could be controlled by injection of 5 percent morruhate sodium in the proximal gastric region 1 to 2 cm distal to the LES at flexible endoscopy and suggested that the proximal gastric sclerosis caused by the injection formed an effective antireflux barrier. Donahue P E et al. 1990, Gastrointest Endosc 36:253-6; Donahue P E et al. 1992, World J Surg 16:343-6. Endoscopic proximal gastric sclerosis induced by Nd:YAG laser has also been shown to create a potential reflux barrier in dogs. McGouran R C M and Galloway J M 1990, Gastrointest Endosc 36:531-2. Recently, Harrison et al. described a method of forming a flap valve at the GEJ by creating an intussusception of esophagus into stomach. U.S. Pat. No. 5,403,326. LoCicero disclosed an endoscopic method for reducing gastroesophageal reflux in U.S. Pat. No. 5,887,594.